Images in cardiovascular medicine. Left ventricular pseudoaneurysm: a late complication of low-energy DC ablation.
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Aneurysm, False↗
Biomedical subjects
Paul Khairy
Publications and source records attributed to Paul Khairy.
Transvenous pacing leads and systemic thromboemboli in patients with intracardiac shunts: a multicenter study.
BACKGROUND: The risk of systemic thromboemboli associated with transvenous leads in the presence of an intracardiac shunt is currently unknown. METHODS AND RESULTS: To define this risk, we conducted a multicenter, retrospective cohort study of 202 patients with intracardiac shunts: Sixty-four had transvenous leads (group 1), 56 had epicardial leads (group 2), and 82 had right-to-left shunts but no pacemaker or implantable cardioverter defibrillator leads (group 3). Patient-years were accrued until the occurrence of systemic thromboemboli or study termination. Censoring occurred in the event of complete shunt closure, death, or loss to follow-up. Mean ages for groups 1, 2, and 3 were 33.9+/-18.0, 22.2+/-12.6, and 22.9+/-15.0 years, respectively. Respective oxygen saturations were 91.2+/-9.1%, 88.1+/-8.1%, and 79.7+/-6.7%. During respective median follow-ups of 7.3, 9.3, and 17.0 years, 24 patients had at least 1 systemic thromboembolus: 10 (15.6%), 5 (8.9%), and 9 (11.0%) in groups 1, 2, and 3, respectively. Univariate risk factors were older age (hazard ratio [HR], 1.05; P=0.0001), ongoing phlebotomy (HR, 3.1; P=0.0415), and an transvenous lead (HR, 2.4; P=0.0421). In multivariate, stepwise regression analyses, transvenous leads remained an independent predictor of systemic thromboemboli (HR, 2.6; P=0.0265). In patients with transvenous leads, independent risk factors were older age (HR, 1.05; P=0.0080), atrial fibrillation or flutter (HR, 6.7; P=0.0214), and ongoing phlebotomy (HR, 14.4; P=0.0349). Having had aspirin or warfarin prescribed was not protective. Epicardial leads were, however, associated with higher atrial (P=0.0407) and ventricular (P=0.0270) thresholds and shorter generator longevity (HR, 1.9; P=0.0176). CONCLUSIONS: Transvenous leads incur a >2-fold increased risk of systemic thromboemboli in patients with intracardiac shunts.
Arteriovenous Shunt, Surgical↗
Wolff-Parkinson-white syndrome in d-transposition of the great arteries and mustard baffle.
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Adult↗
Pregnancy outcomes in women with congenital heart disease.
BACKGROUND: Pregnant women with congenital heart disease are at increased risk for cardiac and neonatal complications, yet risk factors for adverse outcomes are not fully defined. METHODS AND RESULTS: Between January 1998 and September 2004, 90 pregnancies at age 27.7+/-6.1 years were followed in 53 women with congenital heart disease. Spontaneous abortions occurred in 11 pregnancies at 10.8+/-3.7 weeks, and 7 underwent elective pregnancy termination. There were no maternal deaths. Primary maternal cardiac events complicated 19.4% of ongoing pregnancies, with pulmonary edema in 16.7% and sustained arrhythmias in 2.8%. Univariate risk factors included prior history of heart failure (odds ratio [OR], 15.5), NYHA functional class > or =2 (OR, 5.4), and decreased subpulmonary ventricular ejection fraction (OR, 7.7). Independent predictors were decreased subpulmonary ventricular ejection fraction and/or severe pulmonary regurgitation (OR, 9.0) and smoking history (OR, 27.2). Adverse neonatal outcomes occurred in 27.8% of ongoing pregnancies and included preterm delivery (20.8%), small for gestational age (8.3%), respiratory distress syndrome (8.3%), intraventricular hemorrhage (1.4%), intrauterine fetal demise (2.8%), and neonatal death (1.4%). A subaortic ventricular outflow tract gradient >30 mm Hg independently predicted an adverse neonatal outcome (OR, 7.5). Cardiac risk assessment was improved by including decreased subpulmonary ventricular systolic function and/or severe pulmonary regurgitation (OR, 10.3) in a previously proposed risk index developed in pregnant women with acquired and congenital heart disease. CONCLUSIONS: Maternal cardiac and neonatal complication rates are considerable in pregnant women with congenital heart disease. Patients with impaired subpulmonary ventricular systolic function and/or severe pulmonary regurgitation are at increased risk for adverse cardiac outcomes.
Abortion, Spontaneous↗
Pacemaker troubleshooting: when MVP is not the most valuable parameter.
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Aged↗
Concordance between an electroanatomic mapping system and cardiac MRI in arrhythmogenic right ventricular cardiomyopathy.
A 29-year-old man presenting with syncopal ventricular tachycardia was diagnosed with arrhythmogenic right ventricular (RV) cardiomyopathy. Cardiac magnetic resonance imaging (MRI) revealed an unequivocal dyskinetic segment at the basal portion of the RV lateral free wall. Three-dimensional electroanatomic voltage mapping using the EnSite NavX system recorded a low voltage area corresponding to the diseased portion of the right ventricle identified by MRI. This report describes concordance between cardiac MRI and this novel mapping system in arrhythmogenic RV cardiomyopathy.
Adult↗
Inaccuracy of Wolff-Parkinson-white accessory pathway localization algorithms in children and patients with congenital heart defects.
INTRODUCTION: ECG algorithms used to localize accessory pathways (AP) in patients with Wolff-Parkinson-White (WPW) syndrome have been validated in adults, but less is known of their use in children, especially in patients with congenital heart disease (CHD). We hypothesize that these algorithms have low diagnostic accuracy in children and even lower in those with CHD. METHODS: Pre-excited ECGs in 43 patients with WPW and CHD (median age 5.4 years [0.9-32 years]) were evaluated and compared to 43 consecutive WPW control patients without CHD (median age 14.5 years [1.8-18 years]). Two blinded observers predicted AP location using 2 adult and 1 pediatric WPW algorithms, and a third blinded observer served as a tiebreaker. Predicted locations were compared with ablation-verified AP location to identify (a) exact match for AP location and (b) match for laterality (left-sided vs right-sided AP). RESULTS: In control children, adult algorithms were accurate in only 56% and 60%, while the pediatric algorithm was correct in 77%. In 19 patients with Ebstein's anomaly, diagnostic accuracy was similar to controls with at times an even better ability to predict laterality. In non-Ebstein's CHD, however, the algorithms were markedly worse (29% for the adult algorithms and 42% for the pediatric algorithms). A relatively large degree of interobserver variability was seen (kappa values from 0.30 to 0.58). CONCLUSIONS: Adult localization algorithms have poor diagnostic accuracy in young patients with and without CHD. Both adult and pediatric algorithms are particularly misleading in non-Ebstein's CHD patients and should be interpreted with caution.
Adolescent↗
Arrhythmias in adult congenital heart disease.
Recent advances in pediatric cardiology and cardiac surgery have allowed a rapidly expanding population of patients with congenital heart disease to thrive well into their adult years. Often after prolonged uneventful clinical courses as children and adolescents, arrhythmias may surface later in life. These arrhythmias are a major source of morbidity. In addition, sudden death is the leading cause of mortality in adult patients with congenital heart disease. This review highlights the various types of brady- and tachyarrhythmias encountered in the more common forms of adult congenital heart disease and explores prognostic implications and therapeutic options.
Adult↗
Transcatheter mapping and ablation of arrhythmias in the coronary sinus.
The coronary sinus (CS) is a complex structure of particular interest to cardiac electrophysiologists. It is exploited as an anatomical reference, a site to record left-sided atrial and ventricular signals and for cardiac resynchronization therapy. Perhaps less appreciated, it may itself serve as a substrate for arrhythmias. It is now increasingly recognized that arrhythmias may be targeted by transcatheter ablation within the CS. This review summarizes pertinent anatomic considerations, explores the relationship between the CS and various arrhythmia substrates, elaborates on current indications for intra CS ablation and addresses efficacy and safety concerns associated with transcatheter ablation.
Arrhythmias, Cardiac↗
Low-molecular-weight heparin in pregnant women with prosthetic heart valves.
BACKGROUND AND AIM OF THE STUDY: Low-molecular-weight heparin (LMWH) is considered a recommended anticoagulation option in pregnant women with prosthetic heart valves. However, few data are available regarding the efficacy and safety of LMWH in this setting. METHODS: In 1999, the authors' institution developed a standardized anticoagulation protocol for pregnant women with prosthetic heart valves, which included LMWH administered between six and 12 weeks' gestation, and after 36 weeks, with prespecified target levels, and additional low-dose aspirin. Herein is presented the initial experience using this anticoagulation regimen. RESULTS: Among five women with prosthetic heart valves treated with LMWH during part of their pregnancy, four had uneventful pregnancies while one suffered a coronary artery embolus. A review is provided of the current state of knowledge regarding anticoagulation in pregnancy, with emphasis placed on the importance of strict monitoring of anticoagulation levels. CONCLUSION: Given the drawbacks of other forms of anticoagulation, and within the constraints of available data, LMWH appears--when administered with caution--to be an acceptable alternative in pregnant women with prosthetic heart valves.
Adult↗
Angiotensin receptor blockade and exercise capacity in adults with systemic right ventricles: a multicenter, randomized, placebo-controlled clinical trial.
BACKGROUND: Pharmacological blockade of the renin-angiotensin system improves exercise tolerance in patients with left ventricular dysfunction, yet its impact on patients with systemic right ventricles (RVs) remains unknown. METHODS AND RESULTS: A multicenter, randomized, double-blind, placebo-controlled, crossover clinical trial was performed to assess the effects of losartan on exercise capacity and neurohormonal levels in patients with systemic RVs. Of 29 patients studied (age, 30.3+/-10.9 years), 21 had transposition of the great arteries with a Mustard baffle, and 8 had congenitally corrected transposition of the great arteries. Baseline values were as follows: VO2max, 29.8+/-5.6 mL.kg(-1).min(-1) (73.5+/-12.9% predicted value); RV ejection fraction, 41.6+/-9.3%; N-terminal pro brain natriuretic peptide (NT-proBNP), 257.7+/-243.4 pg/mL (normal <125 pg/mL); and angiotensin II, 5.7+/-4.9 pg/mL (normal <5.0 pg/mL). Comparing losartan to placebo showed no differences in VO2max (29.9+/-5.4 versus 29.4+/-6.2 mL.kg(-1).min(-1); P=0.43), exercise duration (632.3+/-123.0 versus 629.9+/-140.7 seconds; P=0.76), and NT-proBNP levels (201.2+/-267.8 versus 229.7+/-291.5 pg/mL; P=0.10), despite a trend toward increased angiotensin II levels (15.2+/-13.8 versus 8.8+/-12.5 pg/mL; P=0.08). CONCLUSIONS: In adults with systemic RVs, losartan did not improve exercise capacity or reduce NT-proBNP levels. Minimal baseline activation of the renin-angiotensin system may explain this lack of benefit and imply an alternative pathophysiological mechanism for the progressive ventricular dysfunction and impaired exercise capacity observed in such patients.
Adult↗
Cardiac resynchronization therapy in congenital heart disease.
While cardiac resynchronization therapy (CRT) is of proven benefit in selected patients with severe ischemic or dilated cardiomyopathy, refractory symptoms, and conduction delay, extrapolation to congenital heart disease is not straightforward. This rapidly expanding patient population commonly suffers from heart failure, particularly in the presence of a single or systemic right ventricle. Surgical repair may also contribute to ventricular asynchrony. In this systematic review, the current state of knowledge regarding CRT in congenital heart disease is presented. Issues specific to congenital heart disease including right bundle branch block, right (pulmonary) ventricular dysfunction, systemic right ventricular dysfunction, and single ventricle dysfunction are explored. Evidence-based CRT applications for each of these particular conditions are reviewed. Initial experience with CRT in the acute postoperative setting and longer-term, including our own, is elaborated. Unlike standard indications based on multiple randomized clinical trials, supporting evidence for CRT in congenital heart disease is limited to case reports, case series, and small experimental crossover studies in the acute postoperative setting. The heterogeneous patient population, technical limitations from patient size, vascular access issues, and unique forms of ventricular asynchrony further obscure the selection of potential beneficiaries. Despite these limitations, experience thus far has been favorable. Quality of current data precludes definitive evidence-based recommendations, but optimistic initial results suggest that research endeavors in this field should be pursued. Multicenter prospective collaborative efforts are to be encouraged.
Cardiac Pacing, Artificial↗
Inability to cannulate the coronary sinus in patients with supraventricular arrhythmias: congenital and acquired coronary sinus atresia.
We report 4 cases of congenital and acquired coronary sinus ostial atresia incidentally found during electrophysiologic assessment for supraventricular arrhythmias. Congenital variants consisted of coronary sinus drainage predominantly via persistent left superior vena cavae and partial coronary sinus unroofing into the left atrium. The acquired variant was inadvertently produced during surgery for cor triatriatum. A variety of electrophysiologic substrates including right and left-sided accessory pathways and both typical and atypical AV nodal reciprocating tachycardia were identified. Approaches to imaging and accessing the coronary sinus when the os cannot be cannulated are discussed, including a search for right atrial accessory venous collaterals, venography to rule-out a persistent left superior vena cava, and coronary angiography.
Adolescent↗
Atrial fibrillation: basic and clinical research at the Montreal Heart Institute.
The present article reviews pertinent contributions from the Montreal Heart Institute, Montreal, Quebec, to the understanding of the mechanisms and treatment of atrial fibrillation. The article discusses the usefulness of anticoagulant therapy, antiarrhythmic drug therapy for sinus rhythm maintenance, the electrophysiological basis of atrial fibrillation and the investigation of new energy sources for catheter ablation. Future directions at the Montreal Heart Institute are also briefly addressed.
Academies and Institutes↗
Morphology of bicuspid aortic valve in children and adolescents.
OBJECTIVES: The aim of this study was to determine the relationship between aortic valve morphology and valve dysfunction. BACKGROUND: The morphology of the bicuspid or bicommissural aortic valve (BAV) may predict the severity of valve dysfunction. Therefore, we assessed the relationship between BAV, aortic coarctation, and the degree of valve pathology in children. METHODS: A retrospective review of 1,135 patients with BAV who were identified between 1986 and 1999 was performed. Patients younger than 18 years of age with BAV that was identifiable via echocardiography were included. The most recent or last study of each patient before intervention or endocarditis was reviewed. Mild stenosis was defined as a valve gradient > or =2 m/s, moderate or greater aortic stenosis as > or =3.5 m/s. Aortic regurgitation was quantified using standard criteria. RESULTS: Median age was 3 years (range, 1 day to 17.9 years), and 67% of the patients were male. Right-coronary and left-coronary leaflet fusion were the most common types of BAV (70%). Aortic stenosis that was moderate or greater was observed most often in patients with right-coronary and non-coronary leaflet fusion (odds ratio 2.4, 95% confidence interval 1.6 to 3.6; p < or = 0.001). Similarly, right-coronary and non-coronary leaflet fusion was more often associated with moderate aortic regurgitation or greater (odds ratio 2.4, 95% confidence interval 1.2 to 4.7; p = 0.01). The majority of patients with aortic coarctation had fusion of the right-coronary and left-coronary leaflets (89%), and aortic coarctation was associated with lesser degrees of valve stenosis or regurgitation. CONCLUSIONS: Analysis of BAV morphology is of clinical and prognostic relevance. Fusion of the right-coronary and non-coronary leaflets was associated with more significant valve pathology, whereas fusion of the right-coronary and left-coronary leaflets was associated overwhelmingly with aortic coarctation and less aortic valve pathology.
Adolescent↗
Value of programmed ventricular stimulation after tetralogy of fallot repair: a multicenter study.
BACKGROUND: Studies have consistently shown that ventricular tachycardia (VT) and sudden cardiac death (SCD) complicate the long-term outcome after tetralogy of Fallot repair, yet the diagnostic and predictive value of electrophysiological testing in this population is uncertain. METHODS AND RESULTS: A multicenter cohort of 252 patients with repaired tetralogy of Fallot undergoing programmed ventricular stimulation was followed up for 18.5+/-9.6 and 6.5+/-4.5 years after corrective surgery and electrophysiological testing, respectively. Clinical VT and/or SCD occurred in 24.6%. Sustained monomorphic VT and polymorphic VT were induced in 30.2% and 4.4%. Including polymorphic VT in the definition of inducibility improved sensitivity (66.1+/-6.0% versus 77.4+/-5.3%, P=0.0082) with a marginal reduction in specificity (81.6+/-2.8% versus 79.5+/-2.9%, P=0.0455). Positive and negative predictive values were 55.2+/-5.3% and 91.5+/-2.2%. Independent risk factors for inducibility were age at study > or =18 years (OR, 3.3), palpitations (OR, 2.8), prior palliative surgery (OR, 3.1), modified Lown criteria > or =2 (OR, 5.6), and cardiothoracic ratio > or =0.6 (OR, 3.3). Event-free survival rates in noninducible and inducible patients at 1, 5, 10, and 15 years were 97.9%, 92.8%, 89.3%, and 89.3% versus 79.4%, 62.6%, 58.7%, and 50.3%, respectively (P<0.0001). Both inducible monomorphic VT [relative risk (RR), 5.0; P=0.0002] and polymorphic VT (RR, 12.9; P<0.0001) predicted future clinical VT and SCD. In a multivariate analysis, inducible sustained VT was an independent risk factor for subsequent events (RR, 4.7; 95% CI, 1.2 to 18.5; P=0.0268). CONCLUSIONS: Programmed ventricular stimulation is of diagnostic and prognostic value in risk stratifying patients with repaired tetralogy of Fallot. In this patient population, inducible sustained polymorphic VT should not be disregarded as nonspecific.
Adolescent↗
Radiofrequency catheter ablation of ventricular tachycardia in children and young adults with congenital heart disease.
OBJECTIVES: The aim of this study was to expand data on outcomes for radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in young patients and to identify obstacles to success. BACKGROUND: Ablation of VT is performed infrequently in young patients. Published experience has been limited to case reports and small descriptive series. METHODS: A retrospective review of 97 consecutive VT ablation procedures involving 62 patients at a single institution from 1990 to 2003 was undertaken. All intention-to-treat procedures were analyzed. RESULTS: Mean age was 13.9 +/- 9.4 years. Procedures were categorized according to VT mechanism as follows: idiopathic right ventricle (n = 37); idiopathic left ventricle (n = 24); congenital heart disease (n = 20); or other structural disease (n = 16). Acute success was achieved in 58 (60%) of 97 procedures. Of the 39 failures, 33 were aborted cases due to inability to induce sufficient ectopy for mapping in 12, high-risk location near the His bundle or coronary artery in 11, unstable VT in 7, and anatomic obstacles in 3. Recurrence rate after acutely successful RFCA was 34% (20/58 procedures) at a mean follow-up of 3.8 +/- 2.0 years. Ultimately, long-term success was achieved in 38 (61%) of 62 patients after a mean of 1.6 +/- 0.9 procedures, with the highest success rate (87%) for idiopathic left ventricular tachycardia. CONCLUSIONS: When analyzed on a strict intention-to-treat basis, a long-term success rate of 61% is observed with ablation of VT in young patients. Inability to induce stable VT for precision mapping and certain high-risk VT locations can be significant obstacles to success.
Adolescent↗
Long-term outcomes after the atrial switch for surgical correction of transposition: a meta-analysis comparing the Mustard and Senning procedures.
Most adults with regular transposition (the combinations of concordant atrioventricular and discordant ventriculo-arterial connections) have undergone either the Mustard or Senning procedure in childhood. It is unclear whether adverse events differ according to the surgery performed. With this in mind, we conducted a systematic review and meta-analysis to compare long-term outcomes. We searched systematically entries to MEDLINE and EMBASE databases from January 1966 through August 2003, supplementing the search by secondary sources. Comparative studies were required to include at least 10 patients in each cohort of Mustard or Senning procedure, and to report overall survival. Data were extracted by two independent reviewers. We used a component approach to assess quality. On the basis of assessment of heterogeneity, we then used a random-effects model for pooled analyses. In all, we included seven studies, incorporating 885 patients. We found a trend towards lower mortality for the 369 patients undergoing a Mustard procedure when compared to 474 submitted to the Senning operation, with a hazard ratio of 0.63 and 95% confidence intervals between 0.35 and 1.14 (p = 0.13). This trend increased with the size of the sample (p = 0.004). Obstruction in the systemic venous pathway was more common in those having the Mustard procedure, with a risk ratio of 3.5 and 95% confidence intervals from 1.8 to 7.0 (p < 0.001), with a trend towards greater obstruction of the pulmonary venous pathway in those undergoing the Senning procedure, 7.6% vs. 3.8% (p = 0.27). A trend towards fewer residual shunts was observed for those with Mustard baffles, 7.0% vs. 14.1% (p = 0.10). Sinus nodal dysfunction, however, was more common after the Mustard procedure. Data regarding atrial tachydysrhythmias was inconclusive. Systemic cardiac failure and functional capacity, was similar. We conclude that outcomes are not uniform among patients submitted to the Mustard and Senning procedures. Knowledge of such differences may facilitate stratification of risk and follow-up.
Actuarial Analysis↗